Chapter 6 Sensation and Perception 217scraping, even though physiological markers of
stress were the same in both groups (Reuter &
Oehler, 2011).
By the way, did you notice the misspelled
word in the preceding paragraph? If not, probably
it was because you expected all the words in this
book to be spelled correctly.
Simulate the Experiment Ambiguous Figures
at MyPsychLabOur perceptions and expectations are all af-
fected, in turn, by the culture we live in. In a classic
study done in the 1960s, members of some African
tribes were much less likely to be fooled by the
Müller-Lyer illusion and other geometric illusions
than were Westerners. In the West, the research-
ers observed, people live in a “carpentered” world,
full of rectangular structures. Westerners are also
used to interpreting two-dimensional photographs
and perspective drawings as representations of a
three-dimensional world. Therefore, they inter-
pret the kinds of angles used in the Müller-Lyer
illusion as right angles extended in space, a habit
that increases susceptibility to the illusion. The
rural Africans in the study, living in a less carpen-
tered environment and in round huts, seemed
more likely to take the lines in the figures liter-
ally, as two-dimensional, which could explain why
they were less susceptible to the illusion (Segall,
Campbell, & Herskovits, 1966; Segall et al., 1999).
Culture also affects perception by telling us
what to notice or ignore. Westerners tend to focus
mostly on the figure in a scene and much less on
the ground. East Asians, in contrast, tend to pay
attention to the overall context and the relation-
ship between figure and ground. In a memory
experiment, Japanese and Americans were shown
animated underwater scenes containing brightly
colored fish that were larger and moving faster
than other objects in the scene. Afterward, bothprove to be the explanation. The image of Jesus
on a garage door in California, mentioned at
the start of this chapter, attracted crowds until it
turned out to be caused by two streetlights that
merged the shadows of a bush and a “For Sale”
sign in the yard.3
emotions. Emotions can also influence our in-
terpretation of sensory information, as when
a small child afraid of the dark sees a ghost in-
stead of a robe hanging on the bedroom door.
Pain, as we noted, is particularly intensified by
negative emotions such as anxiety and sadness.
Conversely, soldiers who are seriously wounded
often deny being in much pain; their relief at be-
ing alive may offset the worry and fear that would
otherwise make their pain worse (although the
body’s own pain-fighting mechanisms may also
be involved). Interestingly, when people perceive
their pain as resulting from another person’s ma-
licious intent (e.g., they think the other person
intentionally stepped on their toe), they feel the
hurt more than they would if they thought it
was simply caused by a clumsy accident (Gray &
Wegner, 2008).4
expectations. The tendency to perceive things
in a certain way based on our expectations
is called a perceptual set. Such sets can come in
handy, helping us fill in words in spoken sentences
when we haven’t really heard every one. But per-
ceptaul sets can also cause misperceptions, as you
can see in the marginal illustration. Expectations
can even reduce our reactions to stimuli that
would otherwise be unpleasant, such as the obnox-
ious sound of fingernails scratching a chalkboard
(human ears are highly sensitive to sounds in that
frequency range). In one study, people who were
told that such sounds were examples of mod-
ern “music” found them less unpleasant than did
people who knew that the sounds were fingernailsperceptual set A ha-
bitual way of perceiving,
based on expectations.PARIS
IN THE
THE SPRINGMost people assume that they perceive reality “as it is.” But culture has a powerful influence on what we notice and
remember. Japanese and other East Asians tend to pay attention to figure and ground equally—in this case, the fish
and its surroundings—whereas Americans tend to pay more attention to the moving fish in the foreground.